Components feeding apparatus

ABSTRACT

In an electronic component mounting apparatus comprises a component feeding section including a feeding table unit loaded with several types of electronic components which feeding table unit is adapted to laterally reciprocate on a base, and stopping at a predetermined position thereby to feed the components continuously to a transfer mechanism, the transfer mechanism for absorbing the electronic components and mounting them on a board on an X-Y table on the other side, the X-Y table fixing and stopping the board to a predetermined position, and a board transport section for transporting the board onto the X-Y table for delivering the board having the electronic components mounted thereon, a component feeding apparatus wherein the component feeding table unit of the component feeding section is divided into a plurality of feeding tables each adapted to be moved individually on a straight line by a drive mechanism, the apparatus further comprising means for moving the table to a predetermined position in opposed relationship with the transfer mechanism in response to a command from the control unit.

BACKGROUND OF THE INVENTION

The present invention relates to a components feeding apparatus formounting a multiplicity of types of small components in position on aboard at high speed, or more in particularly to a components feedingapparatus for a components mounting machine for mounting a multiplicityof types of very small electronic components stored in a tape reel on aprinted board at high speed.

A conventional electronic components mounting machine or apparatus formounting a multiplicity of types of very small electronic components ona printed board, as disclosed in the U.S. Pat. No. 4,307,832, is soconstructed that an electronic components supply unit is disposed on acomponents feeding table which is laterally reciprocated and adapted tostop at a predetermined position, and the components feeding table ismoved each time a transfer head absorbs an electronic component from thefeeding unit.

A plan view of this mechanism is shown in FIG. 7. The electroniccomponent mounting mechanism comprises a body base 1, a componentfeeding table 2, a transfer mechanism using a rotary head or arectangular coordinates type robot (in FIG. 7, the mechanism 3 uses arotary head), and an X-Y table 4. A drive mechanism for the componentsfeeding table 2 includes, as shown in FIG. 8 which is a sectional viewalong line VIII--VIII of FIG. 7, a linear guide 5 with the componentsfeeding table 2 placed thereon, a rack 7, a pinion 8, a reduction gear9, and a motor 10 for driving the components feeding table 2 through thereduction gear 9 by the rack 7 and pinion 8. Another type of drivemechanism includes a DC motor or stepping motor for driving a ballscrew.

Scores to almost a hundred types of tape reel units accommodatingelectronic components therein are disposed in parallel to each other onthe components feeding table 2. This table 2 is positioned at high speedto place any tape reel accommodation the required electronic componentsjust under an absorption point 3a of the transfer mechanism (examplerotary head) 3. In synchronism with the absorption of an electroniccomponent and rotation by the transfer mechanism 3, the X-Y table ispositioned so that a predetermined point coated with an adhesive of theprinted board may come just under the transfer point 3b of the rotaryhead 3. Then, the electronic component is transferred to the printedboard. These steps of operation are performed continuously at highspeed.

In this conventional apparatus, the whole apparatus is stopped tosupplement the components whenever the electronic components aredepleted on the table. For this type of apparatus which transfers asmany as several components per second at high speed, this suspension ofoperation for set-up is a considerable reduction in the workingefficiency.

To the extent that the components handled are about 20 to 40 types, themovable units weigh not more than several tens of kg and the motorcapacity not more than 1 KW, it is possible to use a controller with asmall capacity in this conventional apparatus. However, with an increasein the transfer speed of up to 0.3 to 0.4 seconds per component, andwith an increase in the types of components handled to as many as onethousand, with a corresponding increase in the movable units weight toat least 100 kg, the resultant necessary increase in the capacity of themotor and controller maker this apparatus uneconomical. Further, ifdriven by a ball screw, such an apparatus requires a ball screw as longas several meters, thereby rendering a high-speed drive very difficultin technical aspects of control and vibration.

Furthermore, a heavy item weighing more than 100 kg and moving at highspeed, generates a great vibration and noise, resulting in variousproblems of a reduced mounting performance and a reduced strength ofcomponent members for a high-precision mounting apparatus.

SUMMARY OF THE INVENTION

The object of the present invention is to permit the work ofsupplementing electronic components without suspending the drive of thetable engaged in transfer of electronic components.

In order to achieve the above-mentioned object, there is providedaccording to the present invention a component feeding apparatuscomprising a plurality of component feeding tables, a drive mechanismincluding a linear motor, a transfer mechanism, and means for placingthe tables in position in opposed relationship with the transfermechanism, the feeding tables being drivable individually along the samestraight path.

In view of the fact that there are provided a plurality of componentfeeding tables each drivable and stoppable individually on the samestraight path as described above, a table engaged in the transfer of anelectronic component is capable of high-speed positioning at highprecision, and while the electronic components is being transferred to aboard, the remaining tables are kept stationary on both sides of thebase, thereby making it possible to supplement parts on the stationarytables during the operation of the apparatus. As a result, the workingefficiency can be improved because the apparatus doesn't need to bestopped for refilling the components. Also, with the movable componentsincluding a plurality of component feeding tables, only a table engagedin the transfer work is moved to position while the other tables arekept stationary, and therefore it is possible to reduce the weight ofthe movable components to less than one fourth that with a single tableas in the prior art discussed heretofore, thereby reducing the capacityof the drive unit and the control unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a component mounting apparatuscomprising a component feeding apparatus according to an embodiment ofthe present invention.

FIG. 2 is a plan view showing a table and a transfer mechanism of thecomponent mounting mechanism of FIG. 1.

FIG. 3 is an enlarged sectional view taken in line III--III in FIG. 2.

FIG. 4 is a plan view showing the component feeding apparatus in detail.

FIG. 5 is a diagram showing a configuration of a control unit.

FIG. 6 is a diagram for explaining the operation of the control unit, ofwhich the diagrams (a), (b), (c) and (d) illustrate the sequence ofoperation.

FIG. 7 is a plan view showing a component mounting apparatus comprisinga conventional components supply apparatus.

FIG. 8 is an enlarged sectional view taken in line VIII--VIII in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, FIG. 1 is a perspective view of anelectronic component mounting apparatus according to the inventioncomprising a component feeding unit 101, a transfer mechanism 102, anX-Y table 103, a board receiving section 104a, a board delivery section104b. The board 105 is unloaded from the board receiving section 104a,fixed on the X-Y table 103, and relatively positioned at a point opposedto a mounting head 102a of the transfer mechanism 102.

Electronic component bearing tapes are fixed on tables 15. The tables 15with the tapes are movable laterally so that they can be positionedrelative to the transfer mechanism 102 at absorption points of thetransfer mechanism 102.

The mounting head 102a is lowered and absorbs an electronic component byvacuum, and then makes a half rotation, and is lowered again. Then, theelectronic component is mounted in position on the board 105a on the X-Ytable 103. This series of work is performed at high speed repetitively.

Now, the component feeding table will be explained with reference toFIGS. 2 and 3.

A body base 11, having a length predetermined for allowing the componentfeeding table to run thereon, includes rail-like linear guides 12protruded on both sides on the upper surface, and a slot 14 extendingsubstantially over the whole length of the body base for mounting thelinear motor 13 at the central part thereof. The component feeding tablerunning on the body base 11 requires a length of about several meters intotal if about 100 types of electronic components are to be supplied.The component feeding table is formed by divided tables 15 (15a, 15b,15c, 15d and 15e). With running members 16 provided on both sides of alower surface and engaged with the linear guides 12, each table 15 isadapted to run separately on the linear guides 12. The linear motor 13making up a running (drive) unit includes magnets 17 arranged in opposedrelation to the motor on both sides of the slot 14 and a magneticcircuit 18 formed between the magnets 17. A moving part includes abobbin 19 wound with a coil 19' protruded on the lower surface of thetable 15, which bobbin 19 is inserted in the space between the magnetsin such a manner that the coil 19' cuts the lines of magnetic force 18.Upon energization of the coil 19', the table 15 runs on the linearguides 12 by magnetic force. The magnets 17 making up the stationarysection are arranged over the entire stroke of the body base 11, whilethe moving parts include a plurality of bobbins 19 of the table 15arranged on a straight line, sharing the use of the magnets 17 of thestationary section.

Of all the plurality of tables 15a-15e, only the table 15b opposed tothe transfer mechanism 102 is positioned by being driven at highaccuracy, while the other tables 15a, 15c, 15d and 15e are moved andstopped on the sides of the body base.

As will be seen from the above explanation, the high-accuracy high-speedpositioning operation is required only for the part 1 m long designatedby L near the transfer mechanism 102, and therefore the drive mechanismcan be simplified as shown in FIG. 4. Specifically, in the areas otherthan part L designated by 20, the high-speed, high-accuracy positioningis not required and therefore the magnets 17b of the magnets, thecoercive forces of which are smaller than that of the center portion,are arranged intermittently, so that the drive in the areas is partiallyobtained from inertia. The position of detecting mechanism for thepositioning work, on the other hand, includes a high-resolution linearscale 21 only in the area associated with the part L designated by 20,while in the areas other than L, proximity switches 22 are arranged atintervals, or linear scales having low resolutions are arranged todetect the position of each table. Numeral 23 designates a linear scalehead disposed in opposed relationship with the linear scale on the tableside. The high resolution linear scale, shown schematically at 21 inFIG. 3, can be a conventional linear scale such as an optical linearscale or a magnetic type linear scale.

A control unit according to the embodiment under consideration will beexplained with reference to FIG. 5.

At least two sets of a driver 24 and a servo controller 25 are providedfor a plurality of the linear motors 13a, 13b, 13c, 13d and 13e for aplurality of tables 15a to 15e. A system controller 26 is provided abovethe servo controller 25. A switch 29 for switching the drive circuit 27and the position detection circuit 28 is inserted between the driver 24and each of the linear motors 13a to 13e for the tables. Specifically,the drive circuit 27 is switched to the connection of the coils 19a to19e of the tables, and the position detection circuit 28 is switched tothe heads 23 (23a to 23e) of the linear scale.

The functions of the control unit and the resulting operation of thetables will be explained with reference to FIGS. 6(a), (b), (c) and (d)in that order.

FIG. 6(a) shows the case in which the linear motor 13c loaded with thepart as designated by the system controller 26 is driven by the driver24 to reach a point just under the transfer mechanism 102 until thedeviation of the servo controller 25 becomes zero. In this state, thedrive circuit 27 and the position detection circuit 28 are connected bythe switch 29, and the linear scale 21 is used for positioning as thehigh-precision positioning operation is involved. The linear motors 13a,13b, 13d and 13e for the other tables 15a, 15b, 15d and 15e are kept atthe ends of the body base, and the drive circuit 27 and the positiondetection circuit 28 thereof are not connected nor is the driver 24'used. Upon issuance of a command for using the part placed on the table15d from the system controller 26 at the next moment, the linear motor13c of the table 15c that has thus far conducted the work oftransferring the part is moved to the opposite side of the table 15d inresponse to the signal from the system controller 26 as shown by FIG.6(b), and at the same time, the drive circuit 27' of the driver 24' ofthe switch 29 is connected to the linear motor 13d. As a result, thelinear motor 13d begins to move toward the transfer head at the centerof the apparatus and when it passes the proximity switch 22' nearest tothe linear scale 21 or passes the specific position of the lowresolution linear scale, the command is transmitted to the systemcontroller 26, thereby connecting the position detection circuit 28' bythe switch 29 as shown in FIG. 6(c). The linear motor 13c of the table15c, on the other hand, when it passes the proximity switch 22" or thelike on the opposite side of the proximity switch 22' or the like, isdisconnected with the position detection circuit 28, and when it comesto a predetermined position, is further disconnected with the drivercircuit 27.

Then, as shown in FIG. 6(d), the linear motor 13d of the table 15d isdriven by the commands of the system controller and, stopping at thepredetermined position, conducts the components transfer work throughthe transfer mechanism. This state is the same as that of the linearmotor 13c shown in FIG. 6(a). However, the driver 24, the drive circuit27 and the detection circuit 28 are open, so that the circuits 27 and 28are used for the next switching of the operation of the tables. Theswitching operation is performed in this way, thereby making it possibleto perform the driving and positioning operation with a fewer number ofdrivers and circuits than the linear motors.

Though the switching operation is carried out by high-speed andhigh-accuracy positioning only one divided table, as described withreference to FIG. 5, two divided tables can be positioned simultaneouslyby using two drivers at high-speed and high-accuracy positioning.

Each table is loaded with 20 to 30 types of small electronic parts whichare transferred at high speed to the board. Therefore, the switching isoperated not to jump to the next table but one or any further table butalways to the adjacent table for part transfer work.

Of the plurality of tables, those tables depleted of the electroniccomponent are kept stationary on the sides of the body base, and in thisstate, the electronic components are supplied to them. Even during thiscomponent supplementing work, the electronic components continue to betransferred from the table positioned at the center to the printed boardthrough the transfer mechanism. In this way, the apparatus performs thecomponents-supplementing work by supplying the electronic component tothe component feeding tables while the apparatus is in operation.

It will thus be understood from the foregoing description that accordingto the present invention there is provided a component feeding apparatusin which of all the plurality of tables, only the table which is engagedin the transfer work of the electronic components through the transfermechanism is moved to position at high speed while the other tables arekept stationary, and therefore the weight of the moving components madeup of the tables is reduced to less than one fourth of the conventionalapparatus, thereby reducing the force, vibration or noise generated inthe components of the apparatus for an improved performance andstrength.

We claim:
 1. In an electronic component mounting machine comprising acomponent feeding apparatus including a feeding table unit loaded withseveral types of electronic components which feeding table unit isreciprocated laterally on a base, and stopped at a predeterminedposition for feeding said components continuously to a transfermechanism, a transfer mechanism for conveying said electronic componentsfrom said feeding table unit to a board on an X-Y table and mountingthem on said board, the X-Y table fixing and stopping the board at apredetermined position, and a board transport apparatus for transportingsaid board onto the X-Y table, wherein said feeding table unit of saidcomponent feeding apparatus is divided into a plurality of feedingtables each moved individually on a single straight line by a drivemeans, said drive means moving and positioning said tables separately toa predetermined position in opposed relationship with the transfermechanism in response to a command from a control unit.
 2. A componentfeeding mechanism according to claim 1, wherein said drive means is madeup of a linear motor including a stationary part having a couple ofmagnets arranged .[.along a straight line.]. in spaced relationship witheach other and a moving part having a coil protruded downward from oneof said tables and inserted in the space between the magnets.
 3. Acomponent feeding machine according to claim 2, wherein said magnets arearranged closely in proximity to said transfer mechanism and withgreater intervals at other positions more remote from said transfermechanism, or magnets having high coercive force are arranged closely tosaid transfer mechanism and magnets having low coercive force arearranged at other positions more remote from said transfer mechanism. 4.A component feeding machine according to claim 1, wherein said drivemeans for moving and positioning said tables includes a linear scale ofhigh resolution in the vicinity of the transfer mechanism and aproximity switch or a low resolution linear scale at the other positionsmore remote from said transfer mechanism.
 5. A component feeding machineaccording to claim 4, wherein said control unit includes a systemcontroller, a plurality of drive circuits, linear scale detectioncircuits, drivers and servo controllers fewer in number than saidtables, said proximity switch or said low resolution linear scaledetecting a table approaching the region covered by the high resolutionlinear scale thereby to switch the connections of said drive circuitsand said linear scale detection circuits to said tables simultaneously.6. A component feeding machine according to claim 1, wherein each tableincludes a component storage unit installed thereon for sequentiallydelivering the component.[.,.]. thereby forming .[.a.]. .Iadd.the.Iaddend.component feeding apparatus.Iadd., .Iaddend..[.including a.]..Iadd.said .Iaddend.transfer mechanism .[.for conveying.]..Iadd.selectively absorbs and holds .Iaddend.the components .[.on.]..Iadd.from .Iaddend.the table .Iadd.and transfers said components.Iaddend.to the board .[.and an.]. .Iadd.on said .Iaddend.X-Y table.[.having said board disposed thereon for.]..Iadd., said X-Y table.Iaddend.placing said board at a predetermined positiontwo-dimensionally.
 7. An electronic component feeding apparatus for anelectronic component mounting machine, comprising a supply table dividedinto a plurality of tables having several types of electronic componentsmounted thereon, a drive means for moving each table on the samestraight line separately and for placing each table at a predeterminedposition on said line which is opposed to a transfer mechanism inresponse to a command from a control unit, the tranfer mechanismconveying said electronic components from said tables to a board placedon an X-Y table and mounting said components on said board, the X-Ytable fixing and stopping the board at a predetermined position, and aboard transport section for transporting said board on said X-Y tableand delivering the board having the electronic components mountedthereon. .Iadd.8. An electronic component mounting machine comprising:aplurality of feeding table means for accommodating several types ofelectronic components; transfer means for transferring said electroniccomponents from the feeding table means to a predetermined position andmounting the electronic components at a predetermined position on acomponent receiving means; and means for individually moving said tablemeans and stopping the table means at a predetermined position withrespect to said transfer means. .Iaddend. .Iadd.9. An electroniccomponent mounting machine comprising: a plurality of feeding tablemeans separately movable between a feeding position for enabling afeeding of the electronic components and a loading position for enablinga loading of the electronic components on the feeding table means; andmeans for conveying said electronic components from said feeding tablemeans in the feeding position to a predetermined position and mountingthe components on a component receiving means. .Iaddend. .Iadd.10. Anelectronic component mounting machine comprising a component feedingapparatus including a plurality of table means laterally reciprocablymounted on a base for accommodating a plurality of types of electroniccomponents, said feeding table means being adapted to be stopped at apredetermined position for continuously feeding said electroniccomponents, a transfer means for conveying said electronic componentsfrom said feeding table means to a board and mounting the electroniccomponents at predetermined positions on said board, and drive means forseparately moving and positioning said plurality of table means to apredetermined position in an opposed relationship with the transfermeans. .Iaddend. .Iadd.11. An electronic component mounting machinecomprising: a component feeding apparatus including a plurality offeeding table means for accommodating several types of electroniccomponents, said feeding table means being laterally reciprocablymounted on a base and being adapted to be stopped at a predeterminedposition for continuously feeding said electronic components, a transfermeans for conveying said electronic components from said feeding tablemeans to a board and mounting said electronic components atpredetermined positions on said board, and drive means for individuallyand separately moving and positioning said table means to apredetermined position in an opposed relationship with respect to thetransfer means in response to a command signal. .Iaddend.